What you're looking for is jackd
. Use apt-get
to get it and start it by typing jackd -d dummy
Dummy being the dummy driver for audio. If you've got ALSA installed and working, then replace dummy with alsa. I'd suggest looking around online for some help with running jackd or look at the man page for it. It's new to me too, so mess around with commands until good things happen
After you get jackd running at the command line then open up ardour. Things are a bit messed up with me and I have to sudo ardour
to get it to go. Ardour is messed up for me with bad colors for the top menu and nothing shows up on the mixer controls area. I believe there is some config file you can change to fix the colors, but it didn't work for me.